Lifting-jack



A TTOHN E YS.

Patented July 9, 1895l i 6 e e.

LIFTING JACK.

H. HOLAHAN.

(No Model.)

NITED STATES [PATENT OFFICE.

HARVEY HOLAHAN, OF HARVEY, ILLINOIS.

L lFTlNG-JAC K.

SPECIFICATION forming part of Letters Patent No. 542,257, dated July 9,1895.

Application filed April '7, 1894. Serial No. 506,666. (No model.)

To all whom, it may concern.:

Be it known that I, HARVEY HOLAHAN, of Harvey, in the county of Cook andState of Illinois, have invented a new and useful Improvement inLifting-Jacks, of which the following is a specification.

My inventionis an improvement in the class of lever lifting-jacks which,while capable of general application, is particularly adapted for use asa car-jack. The features of novelty are the lever and pawl mechanismemployed for raising and lowering the rack or ratchet lifting bar, ashereinafter described.

In the accompanying drawings, Figures l and 2 are partly-sectional sideviews of my jack, showing the position of parts when the rack or lifting-bar is being raised and lowered, respectively. Fig. 3 is a verticalcentral section of the jack, further illustrating the relation andoperation of parts. Fig. 4 is an edge viewof a portion of thejack. Fig.5 is a perspective view of the means for adjusting the pawl-spring. Fig.6 is a central longitudinal view of the lever.

The metal standard A is tubular and provided with a horizontal foot orbase A', also with a lateral brace a, all constructed .integrally. 'Ihelifting rack-bar C, which slides in said standard, has an enlarged headc and a toe c', the latter projecting through a lengthwise slot in thestandard when the rack-bar is raised, but adapted to lie iiush in aslot'in the base A when the rack-bar is lowered.

The rack-bar C is raised and lowered and held locked at any elevation bymeans of two pawls or dogs D E and a lever F. The

rsaid pawls are arranged within'the enlarged V upper portion of standardA, and the lever works through a slot in the same. The lower pawl D ispivoted at its lower end in a recess in the standard, and serves to lockor hold the rack-bar C at any elevation-to which it may be raised. Theupper pawl E is pivoted such engagement by sliding in contact with theinwardly-curved inner wall of the standard; but its action is positivelycontrolled, to a certain extent, by means of a round or flat spring G,whose arrangement is as follows: ItsV lower end is attached to alug onthe side of the locking-pawl D, and its upper end slides freely betweentwo lugs on the side of the upper or lifting pawl E. At a pointintermediate of the two pawls the spring G is connected with a device Hbywhich it may be adjusted, as hereinafter described, for the purpose ofchanging-t'. e., regulating its action on the pawls. The said device His a slide arranged horizontally in a slot in the standard A, and thespring G passes through a slot in its inner end, and its outer end isconnected with a thumb-lever I, by which it is adjusted as required. Thesaid thumb-lever is pivoted to the 'standard A and provided with a pinwhich is located eccentrically and works in vertical slot in the slideH. The inner end of the lever is curved or rounded, and thus adapted tocontact with and act as a cam on -the locking-pawl D, as will bepresently explained. The lever is made in two parts F F, whoseconnection will also be described later;

The operation of the jack, so far as described, is as follows: Supposingthe-liftingl rack-bar C to be near its lowest position (Fig. l) and thethumb-lever I thrown down, then the spring G is held vertical by theslide H or parallel to the rack-bar C, and the main or hand lever F F isinclined upward, while both pawls D and E are engaged with the rack-barC. If now the lever F F be depressed, (see dotted' lines, Fig. 1,) theupper pawl F. will force the rack-bar C upward the distance of thelength of one tooth, while the locking-'pawl D slides over a tooth andengages with it. Then, upon raising the lever F F to its former elevatedposition, the liftingpawl E slides down over a tooth, while the pawl Dremains locked with the rack-bar C and holds it stationary. Upon againreciprocating the lever F F the same operatic-n is repeated, with theresult of raising the rackbar C the same distance as before, and so theoperation goes on until the rack-bar has IOO been raised as high asrequired. If now it be desired to lower the rack-bar C the thumblever Iis reversed or thrown upward, as shown in Fig. 2, whereby the slide H isadjusted or drawn outward and the spring G is retracted or curvedbackward, it being thus put under tension, so that it tends to throw andhold both pawls out of engagement with the rack-bar; but owing to thepressure of the latter on the locking-pawl D the latter is held engagedwith it, while the pawl E is alone held out of engagement with it. Then,upon depressing the main lever F F', the lifting-pawl E slides upwardand engages the rack'bar C and raises it slightly, thus allowing thespring G to throw the pawl D back out of engagement with it. As theleverF F' moves upward to its original position, the rack-bar C slidesdown the distance of one tooth, being supported during such movement onthe upper pawl E; but when the lever is thus rising its cam eudfstrikes(Figs. 1 and 3) upon the head of the locking-pawl D and forces it intoreengagement with the rack-bar C, so as to hold the latter from furtherdescent until the main lever F F' shall be again depressed. Thus theoperation goes on, the pawls being alternately engaged with anddisengaged from the rack-bar C until the latter has been lowered to therequired extent.

The construction of the main lever is as follows: The handle of the sameis fixed in a tapered socket F', whose inner end is pivoted in theconcavity of the longer arm of the lever proper F, and the said socketF' is adjustably connected with such concave arm by means of ascrew-bolt f' and nutf2. Thebolt f' passes through the socket F', andits threaded end through the concave arm F, and the nut f2 is applied onthe upper side of the latter. A spiral spring f3 encircles the bolt j"at a point between the arm and socket.

It will be seen that by adjusting the nut f2 on the screw-holt f theleverproper F may be adjusted with nicety to regulate the action of thelocking-pawl D, so that it will be forced to engage the descendingrack-bar at the instant required.

The spring G has no function save to hold the socket F and the concavearm of the lever proper F' spaced apart to the extent permitted by theadjustment of the nut f2.

A modification is shown in Fig. 6, the spring-bolt and nut beingdispensed with and the required connection between the 1ever proper Fand socket F being made by means of a curved and apertured bar, whichpasses through a slot in the former and is secured by means of across-pin. This two-part construction of lever in either form enables itto be conveniently used under a car.

That I claim isl. In a lifting-jack, the combination with the standard,and a rack-bar adapted to slide in the latter, of the pivoted lever, alifting pawl pivoted to the lever, a locking pawl pivoted to thestandard, aspring extending from one pawl to the other, and connectedwith both on the sides thereof, and a device attached to the standardand holding the spring at a point intermediate of the pawls, as shownand described. p

2. In a lifting-jack, the combination with a hollow standard having,interiorly, an inwardly curved portion at its upper end, of a pivotedlever, a lifting pawl pivoted to the latter, a locking pawl pivoted inthe standard, a spring connected with the pawls for actuating them, andmeans for adjusting the spring for varying its tension and action on thepawls, substantially as shown and described.

3. In a lifting-jack, the combination with the hollow standard havinginteriorly an inwardly curved upper portion, a lever pivoted in thestandard, a lifting pawl pivoted to Said lever, a locking pawl pivotedto the standard, a ribbon spring which is connected with both pawls, aslide attached to the spring and adapted for adjustment horizontally,and means for securing said slide in different adjustments, whereby thespring is held under different tensions as required to act on the pawls,as shown and described.

4. In a lifting-jack, the combination, with the hollow standard havinginteriorly an inwardly-curved portion at its upper end, a pivoted lever,a lifting pawl pivoted to said lever, a locking pawl pivoted in thestandard, a spring which connects said pawls, a horizontal slideconnected with the spring, a lever pivoted to the standard and havingengagement with the slide, whereby the latter may be adjusted and heldlocked as required to change the action of the spring on the pawls, asshown and described.

5. In a lifting-jack, the combination with a hollow standard, andrack-bar sliding therein, of a pivoted lever having its inner endconstructed to act as a cam, a lifting pawl pivoted to such end of thelever, a locking pawl pivoted in the standard, a spring for throwing thelocking pawl out of engagement with the rack-bar, as shown anddescribed, whereby the locking pawl is pushed into reengagement with therack-bar when the cam end of the lever is thrown down, as shown anddescribed.

6. In a lifting-jack, the combination with a hollow standard and arack-bar sliding therein, of a locking pawl pivoted in the standard, alever proper also pivoted in the standard, and having its inner endarranged contiguous to the locking pawl, to adapt it to act as a cam, ahandle socket pivoted to said lever proper, and means for adjustablyconnecting the latter with said socket, substantially as shown anddescribed.

7. In a lifting-jack, the combination with a hollow standard and arack-bar sliding IOO IIO

therein, of a locking pawl pivoted in the proper and Lhesoeket as shownand described, standard, a lever proper also pivoted in the to operateas specified. standard, and having its inner end arranged contiguous tothe locking pawl, to adapt it to HARVEY HOLHAN. 5 act as a cam, handlesocket pivoted. to said Witnesses:

lever proper, and the screw bolb,'nut and J. VAN DELL,

spring arranged in connection with the lever J. S. LAZARUS.

